(a) Field of the Invention
The present invention relates to a hand tool used to clamp and turn pipe fittings, unions, pipe joints, etc., to cause them to inter-engage screwably, and more particularly to a pair of pliers that has a enhanced clamping effects, and that is convenient to operate.
(b) Description of the Prior Art
A conventional pair of pliers is generally F-shaped and includes mainly a handle, a turning knob, and a fixed jaw and a movable jaw capable of relative parallel displacement. Since the fixed jaw and the movable jaw use their parallel planar faces to contact pipes, the acting area is small and slippage may occur when clamping pipes. Besides, in operation, if the turning knob is directly turned to cause the fixed jaw and the movable jaw to clamp the pipe, it will be time-consuming to adjust the turning knob, so that the clamping effect is not satisfactory. If the clearance between the fixed jaw and the movable jaw is set before clamping, the clearance may not be properly set and will need adjustments, which is very inconvenient. Furthermore, in order to adapt to pipes of different diameters, the turning knob has to be turned several rounds to cause the fixed jaw and the movable jaw to open or close in order to arrive at a desired clearance, which is time-consuming and troublesome.